Tone sandhi refers to tone manipulation rules governing the pronunciation of tonal languages. Sandhi in Sanskrit means "putting together". Tone-changing processes are active in all tonal languages, but they seem to be more common in some than in others.

Languages with such rules include:

• Most varieties of spoken Chinese
• Cherokee
• Ewe

In Mandarin Chinese, the most common tone sandhi rule is that the leading syllable in a set of two third-tone syllables is raised to the second tone. For example, nǐhǎo (pinyin), the most common Mandarin greeting, is pronounced níhǎo. Tone sandhi in Hakka is more complex; in Southern Min, more complex still. As an example of how tone sandi may affect meaning, the Taiwanese morphemes kiaⁿ (afraid) and lâng (person) may combine to form the word kiaⁿ-lâng, whose meaning varies according to the tone change. When pronounced "kiaⁿ7-lâng5", it means "to be afraid of people". When pronounced "kiaⁿ1-lâng1", it means "frightful".

Cherokee has a robust tonal system in which tones may be combined in various ways, following subtle and complex tonal rules that vary from community to community. While the tonal system is undergoing a gradual simplification in many areas (no doubt as part of Cherokee's often falling victim to second-language status), the tonal system remains extremely important in meaning and is still held strongly by many, especially older speakers.

See also

• Tone (linguistics)
• Downstep
• Downdrift
• Tone shift
• Tone spread